Streets Magnum $2 Each @ Caltex [WA Only]

Went my local Caltex servo (Ashby, WA) on my way home last night. Had sign advertising Streets Magnum's as 2 for $5. Scanned through at the counter as $2 each.
Receipt attached displays: $2 DEAL WA SPECIAL. Assuming this is available at all WA Caltex stores?
Unsure when this promo started or when it will end as it was unadvertised.

Not as good as the Coles deal this week but excellent price for a single Magnum!
Coles - Streets Magnum 4 pk or 6 pk 360ml-468ml - $3.99 (50% off)